1. Field of the Invention
The present invention relates to a means for altering the shape of a deployed awning to provide under-the-awning protection from solar radiation when the sun is low on the horizon and clearance to open doors. The invention converts a deployed awning into an air foil which minimizes wind effects thereon and enables awning deployment in high wind situations.
2. Discussion of the Related Art
Retractable awnings are deployed from the sides of recreational vehicles, such as motor homes and mobile home trailers, to provide additional living space in the form of an outdoor area adjacent to the RV. Awnings of this type are typically retracted by rolling the canopy material onto a roller tube affixed to the free ends of struts pivotally mounted to the side of the RV. They provide shelter for the RV entrance to prevent rain or snow from entering the RV when the door is open. They are adjustable in pitch to provide a shaded, sheltered area forming an outdoor extension of living space for RV residents when the sun is low on the horizon.
Awnings currently in use provide extremely beneficial services, however, their shape when deployed often fails to provide the protection desired. For instance, when the sun is low on the horizon, the leading edge of the awning must be relatively close to the ground to provide shade. Because of the straight profile of the conventional single plane awning canopy from the RV structure to the awning leading edge, an awning with a low leading edge has a steep canopy or roof pitch which severely limits the usable area under the canopy. RV dimensions necessitate attaching the awning to the side of the structure close to the top of the door opening. Thus when the awning is configured with a steep pitch, it interferes with the door and prevents its opening or chafes against the upper comer of the open door and is thereby quickly destroyed. Furthermore, the large flat surface presented to the wind by awnings configured with a single plane canopy result in the awning fabric bellying up and down to further aggravate the contact between the awning fabric and the door upper edge. This xe2x80x9cflappingxe2x80x9d of the awning fabric creates excessive stress on the awning""s deployment hardware and fittings and the noise created is excessive to the point where it is not only annoying but can cause damage to a person""s auditory system.
Numerous attempts have been made to overcome problems with existing awnings but they have not proved successful or are only marginally so. For instance, various devices in the form of wheels and slides have been placed on the upper corner of doors. These devices are positioned to engage the underside of awnings and prevent the sharp corner of a door from tearing the fabric. Unfortunately, the constant rolling or sliding action of these devices against the fabric causes extreme wear of the awning canopy.
Other attempts to overcome the above problems have involved changes in awning configurations. One such attempt is the use of ribs installed on the underside of the awning fabric. T. Blevins, et al., U.S. Pat. No. 5,449,032 for xe2x80x9cAwning Bowxe2x80x9d, issued Sep. 12, 1995 and U.S. Pat. No. 5,203,393 for xe2x80x9cAwning Support Ribsxe2x80x9d, issued Apr. 20, 1993, are exemplary of the use of such devices to alter the shape of an awning. These devices successfully alter the shape of awnings, but the amount of curvature is limited so they do not overcome the problems associated with steep roof pitches and their installation is difficult as well as time-consuming and dangerous in high wind conditions.
A primary objective of the present invention is to provide a means to impart a Mansard shape to an awning to thereby provide clearance for opening doors and protection against winds and solar radiation when the sun is low on the horizon.
Another objective of the invention is to reshape a retractable RV awning whereby its canopy has two sections, one of which has a steeper pitch than the other to thereby provide clearance for opening doors and shade when the sun is low on the horizon.
A further objective is to provide an apparatus which is easily deployed and works with existing awnings to provide clearance for opening doors and shade when the sun is low on the horizon.
Another objective is to provide an apparatus which is easily deployed and works with existing awnings to reduce canopy wind resistance and thereby minimize fabric bellying.
A further objective is to create an air foil shape of an awning""s fabric whereby wind induced flapping of the awning is minimized.
Another objective is to extend the life of awning fabrics by eliminating excessive wear caused by engagement with doors or other similar openings and flapping under high wind conditions.
A still further objective is to prevent excessive wear of awning deployment hardware caused by windy conditions.
Another objective is to provide an apparatus which is easily deployed and works with existing awnings to reduce wind induced fluttering of canopy edges.
A still further objective is to provide a ridge pole for altering the canopy shape of existing awnings and a support means therefor which includes means to stabilize the edges of the awning canopy.
According to the present invention, an easily deployed ridge pole is used, in combination with standard awning deployment hardware, to change the shape of the canopy fabric of an extended retractable awning. The ridge pole engages the underside of the awning fabric to impart a Mansard shape to the canopy. This shape incorporates first and second planes of canopy fabric wherein the plane closest to the RV, the first plane, has a less steep pitch than the plane furthest from the RV, the second plane. The shape has airfoil qualities which stabilize the effects of high wind velocities on the awning. The shape also provide room under the first, relatively flat plane for doors under the awning to open without engaging the awning fabric. The ridge pole is supported by struts which in some embodiments provide foundations for fabric stabilizing clamps that are affixed to loose edges of canopy fabric.
The ridge pole of the preferred embodiment is fabricated from plastic material having a smooth outer surface, such as PVC pipe. This reduces awning fabric ware. To accomplish its goals, the Mansard shape of the awning must be stable even under high wind loads. This necessitates a rigid ridge pole. The rigidity required of the ridge pole is attained by reinforcing the plastic pipe with a core. Preferably the core is a steel conduit which completely eliminates flexing of the ridge pole. This stabilizes the awning""s canopy shape and eliminates wearing of the fabric against system components. In alternative embodiments the ridge pole may be fabricated from a material which is sufficiently rigid. Thus eliminating the need for a reinforcing core.
By forming a conventional awning into a Mansard shape, the invention creates room for doors under the awning canopy to open. An airfoil is also formed from the awning fabric. This stabilizes the awning in high wind conditions to minimize flapping and its attendant noise and the resultant wear of the awning and its fittings. The mechanics of the airfoil are inherent in a Mansard shape wherein the section of the awning canopy closest to the RV has a relatively flat pitch and the section of the canopy extending from the ridge pole to the leading edge of the awning has a relatively steep pitch. Thus wind flows up the steep pitch and is accelerated over the ridge pole and flat pitch area, creating a partial vacuum similar to that encountered by the high laminar flow over aircraft wings.